#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#define BUF_SIZE 30


int main(int argc, char *argv[])
{
    int sock;
    char msg[BUF_SIZE];
    int str_len;
    socklen_t adr_sz;

    struct sockaddr_in serv_adr;
    struct sockaddr_in from_adr;

    if (argc != 3) {
        printf("Usage: %s <IP> <port>\n", argv[0]);
        exit(1);
    }

    sock = socket(PF_INET, SOCK_DGRAM, 0);
    if (-1 == sock) {
        error_handling("socket creat error");
    }

    memset(&serv_adr, 0, sizeof(serv_adr));
    serv_adr.sin_family = AF_INET;
    serv_adr.sin_addr.s_addr = inet_addr(argv[1]);
    serv_adr.sin_port = htons(atoi(argv[2]));


    while (1)
    {
        fputs("Insert message(q to quit): ", stdout);
        fgets(msg, sizeof(msg), stdin);
        if (!strcmp(msg, "q\n") || !strcmp(msg, "Q\n")) {
            break;
        }

        sendto(sock, msg, strlen(msg), 0,
            (struct sockaddr *) &serv_adr, sizeof(serv_adr));
        adr_sz = sizeof(from_adr);
        str_len = recvfrom(sock, msg, BUF_SIZE, 0, 
            (struct sockaddr*)&from_adr, &adr_sz);
        printf("Message from server: %s", msg);
    }
    close(sock);
    
    return 0;
}


void error_handling( char *msg) {
    fputs( msg, stderr );
    fputc('\n', stderr);
    exit(1);
}